The use of renewable sources of raw materials for producing chemical materials for applications in wide ranging industrial and consumer products is important for a sustainable future. The principles of green chemistry, as put forth in the widely acknowledged book “Green Chemistry Theory and Practice” by Paul Anastas and John Warner include the minimizing of waste streams in chemical processes, and biodegradation or recycling of chemical materials at the end of the use cycle. The use of naturally derived biodegradable raw materials to produce additives for use in consumer products by processes that generate minimal waste streams supports sustainability and the principles of green chemistry.
The use of chemically modified protein materials in laundry products is known. U.S. Pat. No. 5,112,520 discloses isolated vegetable proteins modified with anionic or cationic functionality which are shown to have soil antiredeposition properties in laundry detergents. U.S. Pat. No. 5,073,292 discloses cationically charged modified proteins as enzyme stabilizers in laundry detergents. U.S. Pat. No. 5,207,941 discloses vinyl monomers grafted to isolated proteins as detergent ingredients to improve detergency and reduce greying. In a paper presented at CESIO Paris in June 2008 entitled “Use of Protein Based Surfactants in Homecare and Laundry Applications”, authored by Alun Barnes, Trevor Blerase, and Harry Motson, a number of applications for cationically modified proteins in laundry products are disclosed. The modified proteins were added to fabric conditioners and provided fiber protection, strengthening of fibers, softening, anti-pilling and antistatic effects, and improved lubricity. They do not disclose the nature of the modification, but state that the proteins become “cationically charged”, and therefore would be expected to be incompatible with detergents comprised of anionic components. U.S. Pat. No. 5,952,288 describes complexes of hydrolyzed proteins and anionic surfactants wherein the anionic surfactant is present at a weight excess over the protein, and wherein the hydrolyzed protein is described as a chemical linker in the formation of microemulsions. U.S. Pat. No. 7,399,495 discloses the addition of soy lecithin to powdered or particulate protein products to improve their dispersibility. US Patent Application 2002/0144951 discloses cationically modified soy protein and soy flour with cationic reagents in an excess amount such that the protein becomes positively charged for use as a coagulant in waste treatment.
It is known that surfactants and in particular sodium lauryl sulfate interact with proteins. See, for example, Vasilescu, et al, Langmuir 1999, 15, 2635-2643; Turro, N. et al, Langmuir 1995, 11, 2525-2533; Moore, P. et al, Langmuir 2003, 19, 1009-1016; and Deo, N. et al, Langmuir 2003, 19, 5083-5088. U.S. Pat. Nos. 4,028,317, 4,029,825 and 4,058,510 describe the use of sodium lauryl sulfate to “complex” the proteins in whey solutions such as cheese and soybean whey to separate the protein from the other whey components by precipitation at the isoelectric point.
The protein compositions used in the examples of the referenced technologies are typically prepared from various protein containing sources that have undergone processing steps to increase and modify the protein content. The processing steps for increasing the soy protein content of defatted soybean materials are described, for example, in “Soybeans, Chemistry, Production Processing, and Utilization”, edited by L Johnson, P. White and R. Galloway. The starting material for the concentrated soy protein products described in this reference is typically defatted soy flakes, or alternatively soy meal or soy flour which are prepared by milling the defatted soy flakes after the extraction of the oil. The soy flakes or flours typically contain 56 to 59 percent protein on a moisture free basis.
Soy protein concentrate is typically produced by at least one ethanol or aqueous ethanol extraction at a ratio of at least 10 parts of solvent to 1 part of defatted soy flakes. The product is spray dried, and the solvent may be recovered. Alternatively the concentrate can be prepared by at least one acid leaching step with water at the isoelectric point of the protein, or about pH 4.5. This process is carried out at 10 to 20 parts by weight of water per part of defatted soy flakes. The separated protein is then neutralized and dried. The soy protein concentrates typically contain 65 to 72 percent protein on a moisture free basis. Thus the production of soy protein concentrate by known methods produces a waste stream of at least 10 parts of water or other solvent per part of defatted soy flakes, and from about 9 percent to about 23 percent of the weight of the starting soy flakes is contained in the waste streams.
Soy protein isolates are typically prepared by a multistep procedure that includes 1) solubilizing the protein in the flakes at a 1:10 to 1:20 solids:solvent ratio at pH 9-11, 2) centrifuging to remove the insoluble fiber, 3) precipitating the protein at pH 4.2 to 4.5 by acidifying, 4) centrifuging to separate the insoluble protein curd, 5) washing the curd with water and centrifuging again, 6) neutralizing the protein with sodium or calcium hydroxide, and spray drying the neutralized suspension. The soy protein isolates typically contain 90-92 percent protein on a moisture free basis. Thus the production of soy protein isolates by known methods produces a waste stream of at least 30 parts of water or other solvent per part of defatted soy flakes, and from about 34 percent to about 39 percent by weight of the starting soy flakes is contained in the waste streams.
Proteins from many animal and vegetable sources have been isolated, processed and/or derivatized and disclosed for use in laundry products. These include as examples, corn, wheat, barley, oats, cottonseed, sunflower seed, peanuts, rapeseed and canola, sesame, safflower, peas, beans, lentils, bacteria, fungi, yeasts, algae, casein, keratin, and collagen. Processing of the proteins from other sources will vary from that described above for soy proteins, but to obtain the proteins in concentrations used in previously disclosed detergent applications, processes similar in complexity to that described for soy protein are typically used. Isolation of protein from canola meal is described, for example, in “Canola Proteins for Human Consumption: Extraction, Profile, and Functional Properties” in Journal of Food Science 2010 Vol 76 No 1 pages 816-828.
The concentration and isolation of the protein fraction from the soy flakes or soy flour clearly involves large volumes of solvents and waste streams, and multiple processing steps. Processing of proteins from other sources varies with the source but also typically involves large volumes of low value waste streams, and multiple processing steps.
There is a need for laundry additives that are 1) biodegradable and biorenewable, 2) produced sustainably with minimum processing steps, solvent use and waste production, and 3) compatible with laundry products containing anionic surfactants.
It is therefore an object of the invention is to provide effective additives for laundry products based on biodegradable and renewable protein sources.
A further object of this invention is to minimize the processing steps and the resulting waste streams in the preparation of protein derived additives for laundry products.
A further object is to utilize minimally processed protein sources to provide more economical additives in the intended applications.
A further object is to provide modified proteins that are compatible with and readily incorporated into the laundry products to which they are added, by the provision of products with a net anionic charge.
A further object is the provision of laundry products comprising additives derived from crude protein sources.